I decided to use my stock steel ds with my 12 bolt. When my car was stock i didnt have any wierd vibrations at higher speeds. Well today i took the car up to 90 mph and as soon as i let off the gas, car vibrated pretty bad, the vibration stoped at around 60 mph. Does this sound like the Ds being out of balance? The weird thing is that everyitng is nice and smooth untill u let of the gas





Marcin

 

Check the pinion tightness, and throw on an aluminum DS. Could also be a shot bearing as well.

Ryan

 

how can it be a pinion?
The rear is pretty quiet, only slight noise at 45-50 mph.
Also what bearing are you talking about?


Thanks

 

I have this exact same problem with my 12 bolt..and ive got the steel driveshaft too...im pretty convinced its gotta be the DS

 

Did you check the pinion angle?

 

how would i go about doing that?
Thanks

 

put the aluminum DS on and problem solved...is 2 fingers (about 3/4 inch) between the DS and the tranny enough of slack?

 

Marcin did you have to shorten your DS? You have a moser right?

 

94foormula has a good point.
It was my understanding that M6 cars will require a 1/2 inch shorter DS with a moser 12 bolt rear.

 

By using a pinion angle checker...duh

Ryan

 

How are your ujoints? Id check them first.

 

Strange units dont require a shorter driveshaft right? I know the Moser does.

 

Strange 12-bolt is OK with the stock DS length. The stock length provides about 1/2" of clearance in the tranny (sounds like about 2 fingers), so it sounds like you are OK. On big HP setups, that clearance needs to step up to 1".

 

I have a similiar vibration with my 12 bolt, which has been somewhat reduced after I had my gears set up. My driveshaft is a shortened steel version. I was going to get a custom aluminum driveshaft and see if the problem goes away.